Year 9 Science · Unit 2 · Lesson 8

Covalent Bonding and Molecular Substances

Foundation Worksheet

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Date

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Learning Goals

Explain how covalent bonds form when non-metal atoms share pairs of electrons.
Distinguish between single, double, and triple covalent bonds using examples.
Compare simple molecular covalent substances with giant covalent structures.

Warm Up

Match each term to its definition

Draw a line connecting each term on the left to its correct definition on the right. Or write the matching letter next to each term.

Term	Your answer	Definition
Covalent bond		A. A covalent structure in which every atom is bonded to others in a continuous 3D network, no discrete molecules (e.g. diamond, SiO₂).
Shared pair		B. A bond in which two pairs of electrons are shared between the same two atoms (e.g. O=O in O₂).
Single bond		C. A bond formed when two non-metal atoms share a pair of electrons to achieve full outer shells.
Double bond		D. One shared pair of electrons counted as belonging to both bonded atoms.
Triple bond		E. A covalent bond involving one shared electron pair (e.g. H–H).
Giant covalent structure		F. A bond in which three pairs of electrons are shared between the same two atoms (e.g. N≡N in N₂).

Your Turn

True or False? Fix the false ones

Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.

Covalent bonds form between two non-metal atoms that share pairs of electrons.

Correct it:

Water (H₂O) has a bent molecular shape because its two lone pairs push the hydrogen atoms closer together.

Correct it:

Diamond has a very low melting point because it is made of carbon, a non-metal.

Correct it:

Nitrogen gas (N₂) contains a triple covalent bond, three shared pairs of electrons between the two nitrogen atoms.

Correct it:

Simple covalent molecules like CO₂ and H₂O have high melting points because their covalent bonds are very strong.

Correct it:

Show What You Know

1. Explain how a covalent bond forms between two hydrogen atoms. What does each atom contribute, and what does each atom gain?

Recall 2 marks

2. Why does diamond have an extremely high melting point while dry ice (solid CO₂) sublimes at −78.5 °C? Both are made from covalent bonds, what is the key structural difference?

Recall 2 marks

Wrap Up

In one sentence, what was the main idea of this lesson?